The OEM head gasket is a 3-layer riveted metal gasket. To a performance tuner, this is also known as a two-for-one special on thin head gaskets. At the next engine teardown, instead of using a full head gasket, convert it to a thin head gasket by taking out the rivets and just using one of the thin side pieces of this head gasket. This will increase the compression ratio of the cylinder by a significant amount, and you are certain to gain more power everywhere… for free!
You can expect about a .5 increase in the compression ratio depending on what your engine setup is. With a stock piston, which gives an actual 8.6:1 compression ratio you can expect it to bump you to about 9:1 compression ratio.
For a big-bore setup, thin reusable copper head gaskets can be purchased from Miller Vintage Cycle.
Pros of using a thin head gasket:
- Increased compression ratio for significantly improved power
- Very inexpensive upgrade for a large payoff when rebuilding a 230 engine
- Should improve fuel efficiency
- Doesn’t require other supporting mods
Cons of using a thin head gasket:
- When used with a high compression piston such as a Wiseco, the compression ratio will land around 10.5:1, which will require premium grade fuel to avoid detonation/pinging.
Page updated 1/12/2017
CRF230F Mods 